The Pill Raises Cervical Cancer Risk

Nov. 8, 2007 -- Women who use oral contraceptives have an increased risk of developing cervical cancer, but the risk
drops quickly once the pill is stopped.

Taking oral contraceptives for five or more years was associated with a
doubling of cervical cancer risk in the newly published study.

But risk returned to that of never-users within a decade of stopping oral
contraceptives.

The new analysis of data from 24 worldwide studies is one of the most
rigorous examinations of cervical cancer risk in oral contraceptive users ever
conducted.

Epidemiologist Jane Green, MD, who led the study team, tells WebMD that the
findings should be seen as good news for women who take the pill or have taken
it in the past.

The study is reported in the Nov. 10 issue of the journal The
Lancet.

"We have known that women on the combined estrogen pill are at increased
risk [for cervical cancer], she says. "What we haven't known is what
happens after they stop taking the pill. Now we know that the risk starts to
fall pretty quickly and has gone away 10 years later."

Cervical Cancer and the Pill

The new analysis of published and previously unpublished data from studies
involving more than 16,500 cervical cancer patients and 35,500 women without
the disease helps to quantify the risk associated with oral contraceptive use
worldwide.

Routine screening for cervical cancer in developed countries like the United
States has led to dramatic reductions in incidence.

For every 1,000 women in more developed countries who use the pill between
the ages of 20 and 30, the researchers estimated that less than one extra
cancer (4.5 instead of 3.8 for never-users) can be expected by the age of
50.

In less developed countries, the risk was estimated to be 8.3 cases per
1,000 decade-long oral contraceptive users, compared with 7.3 cases for every
1,000 never-users of the pill.

The sexually transmitted human papillomavirus (HPV) is a major risk factor for
cervical cancer, but having multiple childbirths is also considered a risk
factor for the disease.

Because of this, any discussion of risk related to use of oral
contraceptives must consider whether women end up having fewer babies because
they take them, says Peter Sasieni, PhD, of London's Wolfson Institute for
Preventive Medicine.